Cofferdam construction



Nom 7, 1939. vl scH|Av| 2,179,429

COFFERDAM CONSTRUCTION Filed Feb. 4, 1959 2 Sheets-Sheet 1 l juan-Hor, xA .uf Tf je hz D J6 h# @Zaai/fge 51) )7Z /g ,l

Nov. 7, 1939. v scHlAvl 2,179,429

COFFERDAM CONSTRUCTION Filed Feb. 4, 1939 2 Sheets-Sheet 2 mmm PatentedNov. 7, 1939 UNITED STATES PATENT @ENCE 4 Claims.

rlhis invention relates to an improved cofferdam and method oiconstructing same.

Drainage structures, tunnels, aqueducts, foundations, and the like,require a relatively deep trench in their construction. While trenchesfor the placement of aqueducts, foundations, and the like may readily beconstructed in dry hard soils, and the construction work carried outtherein without any attendant danger of the trench walls falling in orthe construction work being shifted from its intended position,nevertheless, many soils are soft, damp, and mobile and accordingly theypresent many handicaps in the formation of trenches for the accuratelaying of construction work and for the safety to workmen engagedtherein. Heretofore, in the construction of aqueducts, foundations, andthe like in soft, wet and mobile soils it has been the practice toprovide submerged housings generally known as coerdams .for preventingcaving in of the sides of the trenches during construction as well asfor assuring working room and safety to workmen engaged in the work.

Cofferdams as heretofore constructed or proposed, however, were not'dependable in the building of trenches in soils, particularly when in asemi-fluid condition and possessing a heavy sub-surface pressure such asis found in bogs and mud areas for the reason that they were not capableoi withstanding such sub-surface pressure. This not only resulted inbending, twisting or crushing the structures of the cofferdams but alsoendangered the accurate and intended position of the construction workin the trenches. Furthermore, coierdams as heretofore used or proposedwere not of a character adapting them for expeditious placement, nor didsuch coerdams offer maximum working space without materially weakeningtheir pressure resisting proporties.

It is accordingly a primary object of this invention to provide a methodof expeditiously constructing cofferdams whereby aqueducts, foundations,and the like, may be accurately built without any attendant danger ofdisplacement thereof and with assured safety to, and unobstructedworking space for workmen engaged therein.

A further object of the invention is `the provision or a cofferdamcomprising relatively few strong and durable cooperating parts and whicheiiectively resists sub-surface pressures and provides maximum workingspace therein.

A still further aim is the provision oi a coerdam comprising bracingelements, trench side wall retaining panels held by the bracing ele-(Cl. (i1-34) ments, and a base seal for preciuding the entrance of soilbefore, during or after removal of the soil conned by the panels.

Yet another purpose of the invention resides in a method of constructinga cofferdam whereby soil is positively sealed against admission to atrench during or after construction thereof by removal of the soilwithin the cciierdam.

Further objects and advantages will appear upon consideration of thefollowing detailed description taken in connection with the accompanyingdrawings, wherein:

Fig. l is an end elevational View or" a coiierdam construction inaccordance with one of the embodiments of the invention, the View beingtaken in a direction as indicated by the line i in Fig. 2 and theconcrete seal and sub-floor being in transverse section.

Fig. 2 is a top plan view of the structure illustrated in Fig. 1 with.the top transverse bracing bars omitted for the sake of clarity.

Figs. 3 and 4 are views similar to Fig. l on a smaller scale andrespectively disclosing modiiied forms of construction.

Fig. 5 is a transverse section of a portion of the construction in aplane represented by the line 5 5 in Fig. 3.

Fig. 6 is asimilar transverse section in plane as represented by theline in Fig. 3.

Referring now in detail to the drawings by reference characters, and'wherein like characters designate like parts, and referring iirst toFigs. l and 2, B designates bracing devices, P designates panels, Sdesignates a concrete seal, F designates a concrete sub-floor, pdesignates piles and G and G', respectiveiy, designate the groundsurface prior to and in preparation ior construction of the coierdam.

The bracing devices B each comprise a pair of laterally spaced verticalmembers il), a top driving transverse brace bar i I, a transverse bracebar l2 adjacent the bar il and similar bars i3 and lil adjacent thelower ends of members it. A steel rod i5 preferably extends through. themembers l@ adjacent each of the transverse brace bars I2, I3 and ld forreinforcing the brace device B an r: lr maintaining the bars l2, i3 andlli in rigid Contact with members lil, the brace bars being otherwisesecured to members iii as by nailing, boiting or welding.

As indicated in Fig. 1, the coiferdam is constructed prior to theremoval of all the soil in providing the trench and accordingiy thebracing devices B are driven into the soil by any suitable power meansand as the coierdam is intended for loose mobile soils substantiallylittle resistance will be oiered in driving these devices into place.

The position of the required trench is first determined by excavatingthe soil from the original level G to the level G after which thebracing devices B are driven into position in accurate alignment and inuniformly spaced position as determined by the panel sections laterref-erred to and which may be driven subsequently to or With the deviceB.

The panels P comprise a plurality of inner sections i6 and a pluralityof outer sections I1 in overlapping relation to the inner sections I6.Each of the sections le, l'l is formed in any suitable manner but asshown each comprises a plurality of horizontal sheets i 8 and aplurality of superposed vertical sheets i9 which are secured together inany suitable and desired manner. The inner sections I6 are provided withvertical guide strips 20 for engagement with opposite sides of memberlll for properly positioning the panels relative thereto. Panels P maybe constructed from any desired material and may be of any size or shapefor best accomplishing the desired results.

When the bracing devices B have been driven into place andthe panelsections i6 and Il positioned as indicated particularly in Fig. 2, thesid-e Walls of the required trench will be effectively spacedirrespective of the sub-surface pressure, which is great in loose mobilesoils, and the overlapping panels l6 and I1 will prevent loose mobilesoils from seeping in from said side walls.

In the constructions requiring thempiles p are driven after theplacement of the bracing devices and the panels. The piles are driven indownwardly diverging relation as indicated for maximum bracing effect.

After the driving of the piles the concrete base seal S is positioned asby means of a tremie fuse or by chuting or dumping. This concrete willharden after being introduced and will form a bottom sea-l therebypreventing mud, ooze, r other uid or liquid material working upwardbefore, during, or after excavation. It will now be seen that the panelsP and bottom seal S will effectively enclose the soil within the panelsagainst ingress of other soil or liquid whereby after excavation theresulting trench will be dry and its walls eiectively braced in xed andimmovable position. The concrete seal will also aid in materiallybracing the devices B and panels P and will also lock the piles ppermanently together. I-Iaving placed the seal S the soil is excavatedfrom between the panels P to the seal S. The piles p are thereafter cutoil? at positions substantially as represented by the dotted lines lafter which' the concrete sub-oor F is laid in readiness for theparticular construction work within the trench.

Thus it will be seen that a cofferdam is provided by a relatively simplemethod and its formation is such as to effectively brace the walls ofthe trench and positively preclude the ingress of soil or moisture andby cutting the piles off at the lines l unobstructed working space isavailable. The assembly shown in Figs. 1 and 2 is preferably left inplace.

As the construction of the cofferdam may be materially reduced inexpense upon removal of the assemblies for use in subsequent coierdamconstructions, the invention includes a form of construction asillustrated in Fig. 3 wherein provision is made for ready removal of theassemblies.

As indicated in this gure the transverse brace bars l2', I3 and I4 areall positioned above the concrete seal S as well as the sub-door F andan additional transverse brace bar 22 is disposed adjacent the lowerends of the members I0. Also added intersecting braces 23 are providedand reinforcing brace members 24 are secured to members l0 and the toptransverse brace bar Il.

Due to the position of brace bars I2', I3 and lf3 and in view of thefact that the two latter preclude available working space in the trench,such bars are removable and for this purpose are constructed andassembled with the members I0 as indicated in Fig. 5. A strip 25 extendsvertically along the inner wall of each of the members l and isinterrupted at each of the cross bars I2', i3 and I Il and each crossbar is laterally positioned Within the resulting channels provided bysuch interruptions and each bar has an extension 26 seated in adepression in member lil and removably secured to the member as by abolt 2l'. Thus when the assembly is in position and the excavatingcompleted the bolts 21 may be withdrawn and the brace bars laterallyremoved to provide for maximum working room in the resulting trench. Thebraces 23 are also preferably removably secured in position as by bolts28 whereby they may also be withdrawn. The lower brace bar 22 beingbelow the seal S would preclude removal of the braces B if said bar 22is permanently secured to members I0.

As indicated, the brace bar 22 is positioned for positive assembly andbracing action during driving of the bracing devices and while suchdevices remain in position, but will readily admit of removal of thedevices B minus only the brace bar 22. To accomplish this, (see Fig. 6),the strips 25 are reduced at their lower ends for a length substantiallyequal to the thickness of bar 22 as indicated at 29. The bar 22 isprovided with vertical end channels 30 to removably receive thesereduced portions whereby the members l0 may be elevated and leave thebar 22 in position and while driving the shoulders on strips 25, denedby the reduced portions 29, woill urge the bar downwardly with themembers In the form according to Fig. 4 no concrete seal is required assame is replaced by a wood floor 3l resting upon and secured tostringers 32 extending longitudinally between the piles p.

It will be obvious that various modifications and changes may be made inthe invention as disclosed as will be apparent to those skilled in theart. It is contemplated to cover all such and to be limited in thisrespect only as may be necessary the scope of the claims heretoappended.

What I claim and desire to secure by Letters Patent is:

1. A method in sub-surface construction comprising the following steps:driving vertically disposed brace members into the ground inlongitudinally spaced relation, inserting continuous linings at eachside of the brace members, driving piles into the ground within theconnes of the brace members, and providing a bottom seal adjacent thelower ends of the piles.

2. The method according to claim l, comprising the additional steps ofcutting 01T the piles adjacent the bottom seal and providing a subflooron top of the bottom seal.

3. A coferdam construction comprising vertically disposed andlongitudinally spaced brace members driven into the ground, liningpanels positioned on opposite sides of the brace members, a bottom sealadjacent the lower edges of the lining panels, a sub-floor disposed uponthe bottom seal, and piles positioned within the connes of the panelsintermediate the brace members and extending downwardly through thesuboor and seal.

4. The structure of claim 3, in which the top of the piles aresubstantially ush with said sub-Hoor.

VINCENT SCHIAVI.

